Find all School-related info fast with the new School-Specific MBA Forum

It is currently 28 Aug 2014, 19:50

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

My girlfriend leaves Berlin with destination Hamburg at the

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Director
Director
avatar
Joined: 17 Dec 2005
Posts: 555
Location: Germany
Followers: 1

Kudos [?]: 8 [0], given: 0

GMAT Tests User
My girlfriend leaves Berlin with destination Hamburg at the [#permalink] New post 26 Jan 2006, 02:14
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
My girlfriend leaves Berlin with destination Hamburg at the same time I leave Hamburg with destination Berlin and our trains are driving a parallel track with the same length. After our trains pass each other at time X my girlfriend takes 1 hour to reach Hamburg with a train driving 240 km/h and I need 4 hours to reach Berlin. How fast is my train driving?
Manager
Manager
avatar
Joined: 05 Oct 2005
Posts: 201
Followers: 1

Kudos [?]: 0 [0], given: 0

GMAT Tests User
 [#permalink] New post 26 Jan 2006, 09:59
interesting exercise! any OA

My trial

240(X+1)/X+4


IF i am correct I will explain
_________________

when there is a will there is a way

best regards

Senior Manager
Senior Manager
avatar
Joined: 19 Feb 2005
Posts: 492
Location: Milan Italy
Followers: 1

Kudos [?]: 9 [0], given: 0

GMAT Tests User
 [#permalink] New post 26 Jan 2006, 10:16
I actually found a number, 120 km/h, calculations are lengthy though
so I suspect of my answer...
Director
Director
avatar
Joined: 17 Dec 2005
Posts: 555
Location: Germany
Followers: 1

Kudos [?]: 8 [0], given: 0

GMAT Tests User
 [#permalink] New post 26 Jan 2006, 11:03
Actually the solution is a number, the X is just for confusion :wink:
Director
Director
avatar
Joined: 17 Dec 2005
Posts: 555
Location: Germany
Followers: 1

Kudos [?]: 8 [0], given: 0

GMAT Tests User
 [#permalink] New post 26 Jan 2006, 11:42
I case your your calcualtion takes too long, use the following:

g= girlfriend
m= me


Speed of g / speed of m = sqrt(time taken by m after passing X) / sqrt( time taken by g after passing X)

= sqrt(4) / sqrt(1)

= 2/1

So "g" is twice as fast as "m"

m= 120 km/h
Manager
Manager
avatar
Joined: 10 Jan 2006
Posts: 117
Followers: 1

Kudos [?]: 0 [0], given: 0

 [#permalink] New post 26 Jan 2006, 13:25
allabout, Can you please explain the formula used??

Thanks
CEO
CEO
User avatar
Joined: 20 Nov 2005
Posts: 2922
Schools: Completed at SAID BUSINESS SCHOOL, OXFORD - Class of 2008
Followers: 15

Kudos [?]: 79 [0], given: 0

GMAT Tests User
 [#permalink] New post 26 Jan 2006, 14:30
B|-------x km ---------------|-------240 km----------| H

Speed of Girl's train = 240 km/h that of boy = y

Then 240/x = x/240 i.e x*y = 240 * 240

and x/4 = y

Solve these two equations for y, we get y = 120
_________________

SAID BUSINESS SCHOOL, OXFORD - MBA CLASS OF 2008

Senior Manager
Senior Manager
avatar
Joined: 08 Sep 2004
Posts: 258
Location: New York City, USA
Followers: 1

Kudos [?]: 9 [0], given: 0

GMAT Tests User
 [#permalink] New post 26 Jan 2006, 14:51
I think its a pretty straightforward problem. GF takes 1 hr to reach H and BF takes 4 hrs to reach B. So speed of BF's train is 1/4th of speed of GF's train. => the speed of BF's train is 240/4 = 60 km/h.

- Vipin
Director
Director
avatar
Joined: 17 Dec 2005
Posts: 555
Location: Germany
Followers: 1

Kudos [?]: 8 [0], given: 0

GMAT Tests User
 [#permalink] New post 27 Jan 2006, 00:40
Riuscita wrote:
allabout, Can you please explain the formula used??

Thanks


Why exactly sqrt of the respective times, don't know. But here's another fast way, if you feel reluctant with the formula.

1) the ratio of the respective speeds is X+4 : X+1 or 1 : X+1/X+4

2) g has made 240*X km's at time X; m takes 4 hours to cover the distance already traveled by g: 240X/4

So the ratio of speed and distance is

240 : 240X/4 : 1 : X+1/X+4, or, because you have to make the units equally

1 : X/4 : 1 : X+1/X+4

So,

X/4=X+1/X+4

Solve for X

X² + 4X = 4X + 4

X = +- 2, -2 is out because there is no negative time

Plug in

240*2/4=120
Manager
Manager
avatar
Joined: 04 Jan 2006
Posts: 51
Followers: 1

Kudos [?]: 0 [0], given: 0

 [#permalink] New post 27 Jan 2006, 02:35
[quote="ps_dahiya"]B|-------x km ---------------|-------240 km----------| H

Speed of Girl's train = 240 km/h that of boy = y

Then 240/x = x/240 i.e x*y = 240 * 240

and x/4 = y

Solve these two equations for y, we get y = 120[/quote]

Hey PS how do you get 240/x = y/240 and x/4 = y??

I am still stuck at 240(x+1)/x+4

The way I worked it is

total distance travelled by Girlfriend = 240x+240
total distance travelled by guy = xy+4y
I then solved for y. I dont get 120 though
Manager
Manager
avatar
Joined: 13 Dec 2005
Posts: 225
Location: Milwaukee,WI
Followers: 1

Kudos [?]: 6 [0], given: 0

GMAT Tests User
 [#permalink] New post 27 Jan 2006, 07:54
Say the distance between the 2 station is Y

speed of girl's train 240
speed of boy's train S

relative speed of approach is 240 +S

since they cross after X hour so they travelled Y distance in total

so distance =speed * time
Y = (240 +S) * X ----- equation 1

also for girl distance =speed * time
Y = 240 * (x+1) ------ equation 2

for boy distance = speed * time
Y = S * (x+4) ----- equation 3


solve all the above 3 equation and u will get the answer
S =120 km/hrs
x = 2hrs
Y = 720 km
  [#permalink] 27 Jan 2006, 07:54
    Similar topics Author Replies Last post
Similar
Topics:
7 Experts publish their posts in the topic My 4-yr pre-MBA journey finally ends with destination as ISB saicharantej99 7 15 Apr 2014, 10:49
An Mba ? and my girlfriend ? chouky 20 07 Oct 2010, 00:53
hamburger grad_mba 6 02 May 2007, 20:55
Leaving for my test now microjohn 8 11 Aug 2006, 12:16
Is it better to leave my job? tarek99 17 26 Jul 2006, 02:18
Display posts from previous: Sort by

My girlfriend leaves Berlin with destination Hamburg at the

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.